Integrated Pixel Display and Touch Sensor

ABSTRACT

In one embodiment, an apparatus includes a display component comprising a plurality of pixels configured to display an image. The apparatus also includes a touch sensor component configured to detect a touch input. The apparatus additionally includes a touch-screen controller. The touch-screen controller is coupled to the touch sensor component and the display component. The touch-screen controller is configured to generate a drive signal for the touch sensor component using a portion of the display component.

TECHNICAL FIELD

This disclosure generally relates to integrated pixel displays and touchsensors.

BACKGROUND

A touch sensor may detect the presence and location of a touch or theproximity of an object (such as a user's finger or a stylus) within atouch-sensitive area of the touch sensor overlaid on a display screen,for example. In a touch-sensitive-display application, the touch sensormay enable a user to interact directly with what is displayed on thescreen, rather than indirectly with a mouse or touch pad. A touch sensormay be attached to or provided as part of a desktop computer, laptopcomputer, tablet computer, personal digital assistant (PDA), smartphone,satellite navigation device, portable media player, portable gameconsole, kiosk computer, point-of-sale device, or other suitable device.A control panel on a household or other appliance may include a touchsensor.

There are a number of different types of touch sensors, such as (forexample) resistive touch screens, surface acoustic wave touch screens,and capacitive touch screens. Herein, reference to a touch sensor mayencompass a touch screen, and vice versa, where appropriate. When anobject touches or comes within proximity of the surface of thecapacitive touch screen, a change in capacitance may occur within thetouch screen at the location of the touch or proximity. A touch-sensorcontroller may process the change in capacitance to determine itsposition on the touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example touch sensor with an example controller.

FIG. 2 illustrates a profile view of a portion of an example touchscreen in which a pixel layer provides a pixel-drive signal to a displaylayer of a LCD, and a reference voltage layer provides the display layerof the LCD with a reference voltage and provides an integrated touchsensor with a drive signal.

FIG. 3 illustrates a profile view of a portion of an example touchscreen in which a pixel-drive layer provides a pixel-drive signal to adisplay layer of a LCD and a drive signal to an integrated touch sensor,and a reference voltage layer provides a reference voltage for thedisplay layer of the LCD and provides a sense signal to a touch screencontroller.

FIG. 4 illustrates an overhead view of an example touch screen in whichpixel-drive electrodes provide a display portion of a touch screen witha pixel-drive signal and provide an integrated touch sensor of the touchscreen with a drive signal.

FIG. 5 illustrates an overhead view of an example touch screen in whicha reference voltage layer provides a display portion of a touch screenwith a reference voltage and provides an integrated touch sensor of thetouch screen with a drive signal.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates an example touch sensor 10 with an exampletouch-sensor controller 12. Touch sensor 10 and touch-sensor controller12 may detect the presence and location of a touch or the proximity ofan object within a touch-sensitive area of touch sensor 10. Herein,reference to a touch sensor may encompass both the touch sensor and itstouch-sensor controller, where appropriate. Similarly, reference to atouch-sensor controller may encompass both the touch-sensor controllerand its touch sensor, where appropriate. Touch sensor 10 may include oneor more touch-sensitive areas, where appropriate. Touch sensor 10 mayinclude an array of drive and sense electrodes (or an array ofelectrodes of a single type) disposed on one or more substrates, whichmay be made of a dielectric material and/or may be included in a displaystack. Herein, reference to a touch sensor may encompass both theelectrodes of the touch sensor and the substrate(s) that they aredisposed on, where appropriate. Alternatively, where appropriate,reference to a touch sensor may encompass the electrodes of the touchsensor, but not the substrate(s) that they are disposed on.

An electrode (whether a drive electrode or a sense electrode) may be anarea of conductive material forming a shape, such as for example a disc,square, rectangle, thin line, other suitable shape, or suitablecombination of these. One or more cuts in one or more layers ofconductive material may (at least in part) create the shape of anelectrode, and the area of the shape may (at least in part) be boundedby those cuts. In particular embodiments, the conductive material of anelectrode may occupy approximately 100% of the area of its shape. As anexample and not by way of limitation, an electrode may be made of indiumtin oxide (ITO) and the ITO of the electrode may occupy approximately100% of the area of its shape (sometimes referred to as 100% fill),where appropriate. In particular embodiments, the conductive material ofan electrode may occupy substantially less than 100% of the area of itsshape. As an example and not by way of limitation, an electrode may bemade of fine lines of metal or other conductive material (FLM) such asfor example copper, silver, or a copper- or silver-based material andthe fine lines of conductive material may occupy approximately 5% of thearea of its shape in a hatched, mesh, or other suitable pattern. Herein,reference to FLM encompasses such material, where appropriate. Althoughthis disclosure describes or illustrates particular electrodes made ofparticular conductive material forming particular shapes with particularfills having particular patterns, this disclosure contemplates anysuitable electrodes made of any suitable conductive material forming anysuitable shapes with any suitable fill percentages having any suitablepatterns.

Where appropriate, the shapes of the electrodes (or other elements) of atouch sensor may constitute in whole or in part one or moremacro-features of the touch sensor. One or more characteristics of theimplementation of those shapes (such as, for example, the conductivematerials, fills, or patterns within the shapes) may constitute in wholeor in part one or more micro-features of the touch sensor. One or moremacro-features of a touch sensor may determine one or morecharacteristics of its functionality, and one or more micro-features ofthe touch sensor may determine one or more optical features of the touchsensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates)and the conductive material forming the drive or sense electrodes oftouch sensor 10. In certain embodiments, the conductive material usedfor the drive or sense electrodes may also be used for a portion of thedisplay screen (e.g., the same conductive material may be used for thesense electrodes of a touch sensor and for the reference voltage layerof a display screen). In some embodiments, the mechanical stack may bewithin or comprise a portion of a display stack configured to generateimages. As an example and not by way of limitation, the mechanical stackmay include a first layer of optically clear adhesive (OCA) beneath acover panel of a display stack. The cover panel may be clear and made ofa resilient material suitable for repeated touching, such as for exampleglass, polycarbonate, or poly(methyl methacrylate) (PMMA). Thisdisclosure contemplates any suitable cover panel made of any suitablematerial. The first layer of OCA may be disposed between a layer orsubstrate of the display stack and the substrate with the conductivematerial forming the drive or sense electrodes. The substrate with theconductive material may provide a benefit or feature in producing animage (e.g., it may be a layer or substrate found in a typical,non-touch, display stack) or it may be a layer added specifically toprovide a substrate on which the electrodes are formed. In someembodiments, the mechanical stack may also include a second layer ofOCA. In some embodiments, the mechanical stack may also include adielectric layer (which may be made of polyethylene terephthalate (PET)or another suitable material, similar to the substrate with theconductive material forming the drive or sense electrodes). As analternative, where appropriate, a thin coating of a dielectric materialmay be applied instead of the second layer of OCA and/or the dielectriclayer. The second layer of OCA may be disposed between the substratewith the conductive material making up the drive or sense electrodes andthe dielectric layer, and the dielectric layer may be disposed betweenthe second layer of OCA and another layer of the display stack. As anexample only and not by way of limitation, the cover panel may have athickness of approximately 1 mm; the first layer of OCA may have athickness of approximately 0.05 mm; the substrate with the conductivematerial forming the drive or sense electrodes may have a thickness ofapproximately 0.05 mm; the second layer of OCA may have a thickness ofapproximately 0.05 mm; and the dielectric layer may have a thickness ofapproximately 0.05 mm. Although this disclosure describes a particularmechanical stack with a particular number of particular layers made ofparticular materials and having particular thicknesses, this disclosurecontemplates any suitable mechanical stack with any suitable number ofany suitable layers made of any suitable materials and having anysuitable thicknesses.

In particular embodiments, the drive or sense electrodes in touch sensor10 may be made of ITO in whole or in part. In particular embodiments,the drive or sense electrodes in touch sensor 10 may be made of finelines of metal or other conductive material. As an example and not byway of limitation, one or more portions of the conductive material maybe copper or copper-based and have a thickness of approximately 5 μm orless and a width of approximately 10 μm or less. As another example, oneor more portions of the conductive material may be silver orsilver-based and similarly have a thickness of approximately 5 μm orless and a width of approximately 10 μm or less. This disclosurecontemplates any suitable electrodes made of any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In amutual-capacitance implementation, touch sensor 10 may include an arrayof drive and sense electrodes forming an array of capacitive nodes. Adrive electrode and a sense electrode may form a capacitive node. Thedrive and sense electrodes forming the capacitive node may come neareach other, but not make electrical contact with each other. Instead,the drive and sense electrodes may be capacitively coupled to each otheracross a space between them. A pulsed or alternating voltage applied tothe drive electrode (by touch-sensor controller 12) may induce a chargeon the sense electrode, and the amount of charge induced may besusceptible to external influence (such as a touch or the proximity ofan object). When an object touches or comes within proximity of thecapacitive node, a change in capacitance may occur at the capacitivenode and touch-sensor controller 12 may measure the change incapacitance. By measuring changes in capacitance throughout the array,touch-sensor controller 12 may determine the position of the touch orproximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include anarray of electrodes of a single type that may each form a capacitivenode. When an object touches or comes within proximity of the capacitivenode, a change in self-capacitance may occur at the capacitive node andtouch-sensor controller 12 may measure the change in capacitance, forexample, as a change in the amount of charge needed to raise the voltageat the capacitive node by a pre-determined amount. As with amutual-capacitance implementation, by measuring changes in capacitancethroughout the array, touch-sensor controller 12 may determine theposition of the touch or proximity within the touch-sensitive area(s) oftouch sensor 10. This disclosure contemplates any suitable form ofcapacitive touch sensing, where appropriate.

In particular embodiments, one or more drive electrodes may togetherform a drive line running horizontally or vertically or in any suitableorientation. Similarly, one or more sense electrodes may together form asense line running horizontally or vertically or in any suitableorientation. In particular embodiments, drive lines may runsubstantially perpendicular to sense lines. Herein, reference to a driveline may encompass one or more drive electrodes making up the driveline, and vice versa, where appropriate. Similarly, reference to a senseline may encompass one or more sense electrodes making up the senseline, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in apattern on one side of a single substrate. In such a configuration, apair of drive and sense electrodes capacitively coupled to each otheracross a space between them may form a capacitive node. For aself-capacitance implementation, electrodes of only a single type may bedisposed in a pattern on a single substrate. In addition or as analternative to having drive and sense electrodes disposed in a patternon one side of a single substrate, touch sensor 10 may have driveelectrodes disposed in a pattern on one side of a substrate and senseelectrodes disposed in a pattern on another side of the substrate.Moreover, touch sensor 10 may have drive electrodes disposed in apattern on one side of one substrate and sense electrodes disposed in apattern on one side of another substrate. In such configurations, anintersection of a drive electrode and a sense electrode may form acapacitive node. Such an intersection may be a location where the driveelectrode and the sense electrode “cross” or come nearest each other intheir respective planes. The drive and sense electrodes do not makeelectrical contact with each other—instead they are capacitively coupledto each other across a dielectric at the intersection. Although thisdisclosure describes particular configurations of particular electrodesforming particular nodes, this disclosure contemplates any suitableconfiguration of any suitable electrodes forming any suitable nodes.Moreover, this disclosure contemplates any suitable electrodes disposedon any suitable number of any suitable substrates in any suitablepatterns.

As described above, a change in capacitance at a capacitive node oftouch sensor 10 may indicate a touch or proximity input at the positionof the capacitive node. Touch-sensor controller 12 may detect andprocess the change in capacitance to determine the presence and locationof the touch or proximity input. Touch-sensor controller 12 may thencommunicate information about the touch or proximity input to one ormore other components (such one or more central processing units (CPUs))of a device that includes touch sensor 10 and touch-sensor controller12, which may respond to the touch or proximity input by initiating afunction of the device (or an application running on the device)associated with it. Although this disclosure describes a particulartouch-sensor controller having particular functionality with respect toa particular device and a particular touch sensor, this disclosurecontemplates any suitable touch-sensor controller having any suitablefunctionality with respect to any suitable device and any suitable touchsensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs),such as for example general-purpose microprocessors, microcontrollers,programmable logic devices or arrays, or application-specific ICs(ASICs). In particular embodiments, touch-sensor controller 12 comprisesanalog circuitry, digital logic, and digital non-volatile memory. Inparticular embodiments, touch-sensor controller 12 is disposed on aflexible printed circuit (FPC) bonded to the substrate of touch sensor10. The FPC may be active or passive, where appropriate. In particularembodiments, multiple touch-sensor controllers 12 are disposed on theFPC. Touch-sensor controller 12 may include a processor unit, a driveunit, a sense unit, a display unit, and a storage unit. The drive unitmay supply drive signals to the drive electrodes of touch sensor 10. Thesense unit may sense charge at the capacitive nodes of touch sensor 10and provide measurement signals to the processor unit representingcapacitances at the capacitive nodes. The processor unit may control thesupply of drive signals to the drive electrodes by the drive unit andprocess measurement signals from the sense unit to detect and processthe presence and location of a touch or proximity input within thetouch-sensitive area(s) of touch sensor 10. The processor unit may alsotrack changes in the position of a touch or proximity input within thetouch-sensitive area(s) of touch sensor 10. The storage unit may storeprogramming for execution by the processor unit, including programmingfor controlling the drive unit to supply drive signals to the driveelectrodes, programming for processing measurement signals from thesense unit, and other suitable programming, where appropriate. Althoughthis disclosure describes a particular touch-sensor controller having aparticular implementation with particular components, this disclosurecontemplates any suitable touch-sensor controller having any suitableimplementation with any suitable components.

Tracks 14 of conductive material disposed on the substrate of touchsensor 10 may couple the drive or sense electrodes of touch sensor 10 toconnection pads 16, also disposed on the substrate of touch sensor 10.As described below, connection pads 16 facilitate coupling of tracks 14to touch-sensor controller 12. Tracks 14 may extend into or around (e.g.at the edges of) the touch-sensitive area(s) of touch sensor 10.Particular tracks 14 may provide drive connections for couplingtouch-sensor controller 12 to drive electrodes of touch sensor 10,through which the drive unit of touch-sensor controller 12 may supplydrive signals to the drive electrodes. Other tracks 14 may provide senseconnections for coupling touch-sensor controller 12 to sense electrodesof touch sensor 10, through which the sense unit of touch-sensorcontroller 12 may sense charge at the capacitive nodes of touch sensor10. Tracks 14 may be made of fine lines of metal or other conductivematerial. As an example and not by way of limitation, the conductivematerial of tracks 14 may be copper or copper-based and have a width ofapproximately 100 μm or less. As another example, the conductivematerial of tracks 14 may be silver or silver-based and have a width ofapproximately 100 μm or less. In particular embodiments, tracks 14 maybe made of ITO in whole or in part in addition or as an alternative tofine lines of metal or other conductive material. Although thisdisclosure describes particular tracks made of particular materials withparticular widths, this disclosure contemplates any suitable tracks madeof any suitable materials with any suitable widths. In addition totracks 14, touch sensor 10 may include one or more ground linesterminating at a ground connector (which may be a connection pad 16) atan edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of thesubstrate, outside the touch-sensitive area(s) of touch sensor 10. Asdescribed above, touch-sensor controller 12 may be on an FPC. Connectionpads 16 may be made of the same material as tracks 14 and may be bondedto the FPC using an anisotropic conductive film (ACF). Connection 18 mayinclude conductive lines on the FPC coupling touch-sensor controller 12to connection pads 16, in turn coupling touch-sensor controller 12 totracks 14 and to the drive or sense electrodes of touch sensor 10. Thisdisclosure contemplates any suitable connection 18 between touch-sensorcontroller 12 and touch sensor 10.

FIG. 2 illustrates a profile view of a portion of an example touchscreen in which a pixel layer provides a pixel-drive signal to a displaylayer of a LCD, and a reference voltage layer provides the display layerof the LCD with a reference voltage and provides an integrated touchsensor with a drive signal. Touch screen 200 includes a stack of layersthat provide both an image, via a display portion, and touch sensing,via an integrated touch sensor. The display portion of touch screen 200is configured to provide images through a two-dimensional array ofpixels. The touch sensor is configured to determine a relative locationof a touch input within touch screen 200. The depicted layers of touchscreen 200 are display layer(s) 210, reference voltage layer 220, sensorsubstrate 230, sense electrodes 240, and pixel layer 250. Additionallayers of touch screen 200 are not depicted. For example, touch screen200 may include one or more layers, materials, and/or components abovesense electrodes 240, below pixel layer 250, and/or in-between any ofthe other depicted layers of touch screen 200.

Display layer(s) 210 may include pixels which provide images for touchscreen 200. Display layer(s) 210 may include any suitable number oflayers of touch screen 200. For example, display layer(s) 210 mayinclude a single display layer or more than one display layer. In someembodiments, display layer(s) 210 may be a liquid crystal layer thatadjusts a polarization of light passing through the layer. In someembodiments, display layer(s) 210 may be the liquid crystal layer andany combination of one or more glass substrate layers with electrodesand/or one or more polarizing filter layers. In some embodiments,display layer(s) 210 may include VCOM layer(s) and/or pixel layer(s).

The color of the pixels of display layer(s) 210 may be determined, inpart, based on an electrical potential between a pixel layer 250 andreference voltage layer 220. The reference voltage may be referred to asa common voltage or VCOM. In addition to providing a reference voltagefor display layer(s) 210, reference voltage layer 220 may also providethe drive signal for a touch sensor. For example, in the embodimentdepicted in FIG. 2, the touch sensor portion of touch screen 200 mayinclude sense electrodes 240, sensor substrate 230, and referencevoltage layer 220. In such an embodiment, reference voltage layer 220may act as the drive electrodes of a touch sensor. This may allow thesame layer, reference voltage layer 220, to provide both a referencevoltage for display layer(s) 210 and a drive signal for a touch sensor.

Reference voltage layer 220 may be electrically conductive so as toprovide both the reference voltage and the drive signal. In certainembodiments, the reference voltage layer 220 may comprise ITO. In someembodiments, reference voltage layer 220 may include fine lines ofmetal. The fine lines of metal may be used to provide both the referencevoltage for display layer(s) 210 as well as the drive signals for thetouch sensor. In some embodiments, the fine lines of metal may bearranged in a mesh configuration. In some embodiments, the fine lines ofmetal may be electrically isolated drive lines that are all pulsedsimultaneously to provide the reference voltage for display layer(s)210. In some embodiments, the fine lines of metal may be electricallyisolated drive lines that are each pulsed one at a time to provide drivesignals to sense electrodes 240. In some embodiments, instead of pulsingeach of the electrically isolated drive lines one at a time to providedrive signals to sense electrodes 240, two or more of the electricallyisolated drive lines (such as, for example, two of the electricallyisolated drive lines, three of the electrically isolated drive lines, orany other number of the electrically isolated drive lines) may be pulsedsimultaneously to provide drive signals to sense electrodes 240.

In the depicted embodiment, sensor substrate 230 is located betweensense electrodes 240 and reference voltage layer 220. In someembodiments, sensor substrate 230 may comprise an additional layer thatwould not be found in a traditional non-touch sensitive LCD displaystack. In some such embodiments, sensor substrate 230 may comprisenon-birefringent material. The use of a non-birefringent material mayavoid undesirable twisting of the light passing through the material. Insome embodiments, sensor substrate 230 may comprise an existing layerthat would be found in a traditional non-touch sensitive LCD displaystack. For example, sensor substrate 230 may be a color filter layer ofan LCD display stack. In some embodiments, sensor substrate 230 maycomprise multiple layers.

Pixel layer 250 may be configured to change the characteristics of thecrystals within display layer(s) 210 (e.g., to change the image to bedisplayed by touch screen 200). In particular embodiments, pixel layer250 may comprise a two-dimensional array of pixel electrodes. The sizeof the two-dimensional array of pixel electrodes may correspond to thenumber of display pixels of touch screen 200 (e.g., each pixel to bedisplayed may have its own respective pixel electrode(s)). In someembodiments, each pixel electrode may be individually controlled togenerate an image.

Although the depicted embodiment includes an LCD display stack, otherembodiments may comprise other types of display stacks (e.g., anydisplay stack that includes a reference voltage layer). For example, insome embodiments, an organic light emitting diode (OLED) display stackmay be used for touch screen 200.

FIG. 3 illustrates a profile view of a portion of an example touchscreen in which a pixel-drive layer provides a pixel-drive signal to adisplay layer of a LCD and a drive signal to an integrated touch sensor,and a reference voltage layer provides a reference voltage for thedisplay layer of the LCD and provides a sense signal to a touch screencontroller. Similar to touch screen 200, touch screen 300 provides bothan image and touch sensitivity. In FIG. 3, touch screen 300 may includeseveral layers. The depicted layers of touch screen 300 include voltagelayer 340, display layer(s) 310, and pixel-drive layer 330. Additionallayers of touch screen 300 are not depicted. For example, touch screen300 may include one or more layers, materials, and/or components abovevoltage layer 340, below pixel-drive layer 330, and/or in-between any ofthe other depicted layers of touch screen 300.

In the embodiment depicted in FIG. 3, the drive and sense electrodes ofa touch sensor are implemented through pixel-drive layer 330 andreference voltage layer 340, respectively. These layers also providetheir traditional functionality for display layer(s) 310. For example,pixel-drive layer 330 may be configured to change the characteristics ofthe crystals within display layer(s) 310 (e.g., to change the image tobe displayed by touch screen 300) and may be configured to provide adrive signal for a touch sensor; and reference voltage layer 340 may beconfigured to provide a reference voltage for display layer(s) 310 andmay be configured to provide sense signals to a touch screen controller(i.e., where the sense signals are provided by the reference voltagelayer 340 as a result of the drive signals provided to the referencevoltage layer 340 by pixel-drive layer 330). In addition, in thedepicted embodiment, display layer(s) 310 may also act as the sensorsubstrate for the touch sensor.

In particular embodiments, pixel-drive layer 330 may comprise atwo-dimensional array of pixel-drive electrodes. The size of thetwo-dimensional array of pixel-drive electrodes may correspond to thenumber of display pixels of touch screen 300 (e.g., each pixel to bedisplayed may have its own respective pixel-drive electrode). While thepixel-drive electrodes may be individually controlled to generate animage, in some embodiments they may be grouped together to provide drivesignals for the touch sensor. For example, one or more rows ofpixel-drive electrodes may be used collectively as a single driveelectrode (e.g., the same drive signal may be sent to all thepixel-drive electrodes within one or more rows pixel-drive electrodes).

In some embodiments, one or both of pixel-drive layer 330 and referencevoltage layer 340 may comprise fine lines of metal. In particularembodiments, the fine lines of metal for pixel-drive layer 330 and/orreference voltage layer 340 may be arranged in a mesh fashion. In someembodiments, fine lines of metal may be connected between thepixel-drive electrodes and a touch screen controller. Although thedepicted embodiment includes an LCD display stack, other embodiments maycomprise other types of display stacks (e.g., any display stack thatincludes a reference voltage layer). For example, in some embodiments,an organic light emitting diode (OLED) display stack may be used fortouch screen 300.

FIG. 4 illustrates an overhead view of an example touch screen in whichpixel-drive electrodes provide a display portion of a touch screen witha pixel-drive signal and provide an integrated touch sensor of the touchscreen with a drive signal. In the depicted embodiment, touch screen 400comprises a four-by-four display with an integrated two-by-two touchsensor. The four-by-four display comprises the individual pixels ofdisplay layer(s) (not depicted). Each pixel of the display has its ownassociated pixel-drive electrode 430. These pixel-drive electrodes 430are grouped into subsets of pixel-drive electrodes 430 to form driveelectrodes 480. The two-by-two touch sensor comprises sense electrodes440 and the two subsets of pixel-drive electrodes 430 that form driveelectrodes 480. In order to form drive electrodes 480, pixel-driveelectrodes 430 are arranged into two subsets (drive electrode 480 a anddrive electrode 480 b), each subset comprises a two-by-four array ofpixel-drive electrodes 430. Controller 450 is separately connected toeach pixel-drive electrode 430 and thus may treat pixel-drive electrodes430 as separate entities when generating an image and collectively (assubsets) when generating a drive signal to determine a location of atouch input. In this embodiment, the sensor substrate (not shown), islocated between sense electrodes 440 and drive electrodes 480.

In the depicted embodiment, touch screen controller 450 is connected tosense electrodes 440 as well as the individual pixel-drive electrodes430 that form drive electrodes 480. This may allow touch screencontroller 450 to both adjust the pixel-drive signal to control theimage generated by touch screen 400 and to manage the drive signal forthe touch sensor used to determine the relative location of a touchinput. Because pixel-drive electrodes 430 are used for both the touchsensor functionality and for creating the displayed image, touch screencontroller 450 may need to synchronize how and when it sends pixel-drivesignals and drive signals.

While the pixel-drive electrodes have been grouped together in rows inthe depicted embodiment, some embodiments may group the pixel-driveelectrodes into clusters (e.g., two-by-two clusters) or may not groupthem together at all. For example, sense electrodes 440 may separatelydetect a touch input based on a change in the charge, capacitance, orelectrical potential from each of the individual pixel-drive electrodes.

FIG. 5 illustrates an overhead view of an example touch screen in whicha reference voltage layer provides a display portion of a touch screenwith a reference voltage and provides an integrated touch sensor of thetouch screen with a drive signal. In FIG. 5, touch screen 500 includestouch screen controller 550 coupled to drive electrodes 530 and senseelectrodes 540. Drive electrodes 530 may be spaced so as to provide areference voltage for a display layer(s) (not depicted). Driveelectrodes 530 may also be configured to provide drive signals to atouch sensor. In some embodiments, drive electrodes 530 may be orientedperpendicularly to the orientation of sense electrodes 540. In someembodiments, drive electrodes 530 may be made of fine lines of metal.Touch screen controller 550 may use drive electrodes 530 to providedrive signals for a touch sensor and to provide a reference voltage fora display layer(s) (e.g., display layer(s) 210 of an LCD display stack).As discussed above with respect to FIG. 4, touch screen controller 550may synchronize the reference voltage and the drive signals being sentover drive electrodes 530. Touch screen controller 550 may then use thesense signal provided by sense electrodes 540 to determine a relativelocation of a touch input.

Although FIGS. 1-5 have been described above as including particularcomponents, the systems of FIGS. 1-5 may include any combination of anyof the described components and any of the options or features describedherein, as would be understood by one of ordinary skill in the art basedupon the teachings of the disclosure. For example and not by way oflimitation, any of the options or features described herein may beutilized in combination with the illustrated embodiments of FIGS. 1-5and/or any number of the other options or features also described hereinas would be understood by one of ordinary skill in the art based uponthe teachings of the disclosure.

Herein, reference to a computer-readable non-transitory storage mediummay include a semiconductor-based or other integrated circuit (IC), suchas for example a field-programmable gate array (FPGA) or anapplication-specific IC (ASIC), a hard disk, an HDD, a hybrid hard drive(HHD), an optical disc, an optical disc drive (ODD), a magneto-opticaldisc, a magneto-optical drive, a floppy disk, a floppy disk drive (FDD),magnetic tape, a holographic storage medium, a solid-state drive (SSD),a RAM-drive, a SECURE DIGITAL card, a SECURE DIGITAL drive, anothersuitable medium, or a suitable combination of these, where appropriate.A computer-readable non-transitory storage medium may be volatile,non-volatile, or a combination of volatile and non-volatile, whereappropriate.

Herein, “or” is inclusive and not exclusive, unless expressly indicatedotherwise or indicated otherwise by context. Therefore, herein, “A or B”means “A, B, or both,” unless expressly indicated otherwise or indicatedotherwise by context. Moreover, “and” is both joint and several, unlessexpressly indicated otherwise or indicated otherwise by context.Therefore, herein, “A and B” means “A and B, jointly or severally,”unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Moreover,reference in the appended claims to an apparatus or system or acomponent of an apparatus or system being adapted to, arranged to,capable of, configured to, enabled to, operable to, or operative toperform a particular function encompasses that apparatus, system,component, whether or not it or that particular function is activated,turned on, or unlocked, as long as that apparatus, system, or componentis so adapted, arranged, capable, configured, enabled, operable, oroperative.

What is claimed is:
 1. An apparatus, comprising: one or more displaylayers within a liquid crystal display (LCD) display stack; a pluralityof sense electrodes within the LCD display stack, the plurality of senseelectrodes configured to detect a touch input; and a reference voltagelayer within the LCD display stack, the reference voltage layerconfigured to provide a reference voltage for the one or more displaylayers and a drive signal detectable by the plurality of senseelectrodes.
 2. The apparatus of claim 1, wherein the reference voltagelayer comprises a plurality of electrically isolated drive lines thatare configured to all be pulsed simultaneously to provide the referencevoltage for the one or more display layers.
 3. The apparatus of claim 1,wherein the reference voltage layer comprises a plurality ofelectrically isolated drive lines that are configured to each be pulsedone at a time to provide drive signals to the plurality of senseelectrodes.
 4. The apparatus of claim 1, wherein the reference voltagelayer comprises a plurality of electrically isolated drive lines,wherein two or more of the plurality of electrically isolated drivelines are configured to all be pulsed simultaneously to provide drivesignals to the plurality of sense electrodes.
 5. The apparatus of claim1, wherein the reference voltage layer comprises fine lines of metal. 6.The apparatus of claim 1, wherein the plurality of sense electrodes aredisposed on a first surface.
 7. The apparatus of claim 6, wherein thereference voltage layer is disposed on a second surface within thedisplay stack.
 8. The apparatus of claim 1, further comprising a touchscreen controller coupled to the plurality of sense electrodes and tothe reference voltage layer, the touch screen controller configured tocontrol the reference voltage for the one or more display layers and thedrive voltage for the plurality of drive electrodes.
 9. An apparatus,comprising: one or more display layers within a liquid crystal display(LCD) display stack, the one or more display layers comprising aplurality of crystals configured to adjust a polarization of lightpassing through the one or more display layers; a reference voltagelayer configured to provide the one or more display layers with areference voltage; a plurality of pixel-drive electrodes configured toadjust the polarization of the light passing through the one or moredisplay layers by adjusting an electrical potential between theplurality of pixel-drive electrodes and the reference voltage layer;wherein the plurality of pixel-drive electrodes are further configuredto provide a plurality of drive signals for a touch sensor; and whereinthe reference voltage layer is further configured to provide sensesignals.
 10. The apparatus of claim 9, wherein the reference voltagelayer comprises fine lines of metal.
 11. The apparatus of claim 9,wherein the plurality of pixel-drive electrodes comprises atwo-dimensional array of pixel-drive electrodes.
 12. The apparatus ofclaim 11, wherein the plurality of pixel-drive electrodes are arrangedin a plurality of subsets, each subset comprising a plurality ofpixel-drive electrodes that collectively provide a drive signal for thetouch sensor.
 13. The apparatus of claim 9, wherein the one or moredisplay layers are between the reference voltage layer and the pluralityof pixel-drive electrodes.
 14. The apparatus of claim 9, furthercomprising a touch screen controller coupled to the reference voltagelayer and the plurality of pixel-drive electrodes, the touch screencontroller configured to adjust the electrical potential at each of theplurality of pixel-drive electrodes to generate an image and to generatea drive signal used to determine a location of a touch input based onthe sense signals from the reference voltage layer.
 15. An apparatus,comprising: a display component comprising a plurality of pixelsconfigured to display an image; a touch sensor component configured todetect a touch input; a touch-screen controller coupled to the touchsensor component and the display component, the touch-screen controllerconfigured to generate a drive signal for the touch sensor componentusing a portion of the display component.
 16. The apparatus of claim 15,wherein the display component comprises an organic light emitting diode.17. The apparatus of claim 15, wherein the display component comprisesone or more display layers of a liquid crystal display.
 18. Theapparatus of claim 15, wherein the touch-screen controller is coupled toa reference voltage layer, the reference voltage layer configured toprovide a reference voltage for the display component and a sense signalto the touch-screen controller.
 19. The apparatus of claim 15, whereinthe touch-screen controller is coupled to a reference voltage layer, thereference voltage layer configured to provide a reference voltage forthe display component and a drive signal for the touch sensor component.20. The apparatus of claim 15, wherein the touch-screen controller iscoupled to a pixel-drive layer, the pixel-drive layer configured toprovide a pixel-drive signal for the display component and a drivesignal for the touch sensor component.